On Tue, Nov 15, 2022 at 12:02 PM Mario Limonciello
<mario.limonciello@xxxxxxx> wrote:
>
> For userspace to be able to analyze how much of a suspend cycle was spent
> in the hardware sleep states userspace software has to use kernel trace
> points paired with the file `low_power_idle_system_residency_us` on
> supported systems.
>
> To make this information more discoverable, introduce a new sysfs file
> to represent the duration spent in a sleep state.
> This file will be present and updated during resume for all suspend
> types.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
> RFC v2->v3
> * Drop one of the sysfs files
> * Use sysfs_emit instead
> * Fix symbol name (s/type/time/)
> * Drop is_visible
> * Use timespec64 type for suspend stats
> * Update documentation
> * Update sysfs file name
> ---
> Documentation/ABI/testing/sysfs-power | 8 ++++++++
> include/linux/suspend.h | 2 ++
> kernel/power/main.c | 15 +++++++++++++++
> kernel/power/suspend.c | 2 ++
> kernel/time/timekeeping.c | 2 ++
> 5 files changed, 29 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
> index f99d433ff311..3abe20c47e08 100644
> --- a/Documentation/ABI/testing/sysfs-power
> +++ b/Documentation/ABI/testing/sysfs-power
> @@ -413,6 +413,14 @@ Description:
> The /sys/power/suspend_stats/last_failed_step file contains
> the last failed step in the suspend/resume path.
>
> +What: /sys/power/suspend_stats/last_total
> +Date: December 2022
> +Contact: Mario Limonciello <mario.limonciello@xxxxxxx>
> +Description:
> + The /sys/power/suspend_stats/last_total file contains
> + the total duration of the sleep cycle.
> + This is measured in microseconds.
> +
Nit/bikeshed: "last_total" seems less straightforward then it should
be? Maybe "total_suspend_time" instead?
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 31ec4a9b9d70..f33012860699 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -6,6 +6,7 @@
> * Copyright (c) 2003 Open Source Development Lab
> */
>
> +#include <linux/acpi.h>
> #include <linux/export.h>
> #include <linux/kobject.h>
> #include <linux/string.h>
> @@ -54,6 +55,11 @@ void unlock_system_sleep(unsigned int flags)
> }
> EXPORT_SYMBOL_GPL(unlock_system_sleep);
>
> +void pm_account_suspend_time(const struct timespec64 t)
> +{
> + suspend_stats.last_total = timespec64_add(suspend_stats.last_total, t);
> +}
> +
> void ksys_sync_helper(void)
> {
> ktime_t start;
> @@ -377,6 +383,14 @@ static ssize_t last_failed_step_show(struct kobject *kobj,
> }
> static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);
>
> +static ssize_t last_total_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + return sysfs_emit(buf, "%llu\n",
> + timespec64_to_ns(&suspend_stats.last_total) / NSEC_PER_USEC);
> +}
> +static struct kobj_attribute last_total = __ATTR_RO(last_total);
> +
> static struct attribute *suspend_attrs[] = {
> &success.attr,
> &fail.attr,
> @@ -391,6 +405,7 @@ static struct attribute *suspend_attrs[] = {
> &last_failed_dev.attr,
> &last_failed_errno.attr,
> &last_failed_step.attr,
> + &last_total.attr,
> NULL,
> };
While not identical, this has some overlap with the logic in
kernel/time/timekeeping_debug.c
I wonder if it would make sense to consolidate some of this accounting?
thanks
-john
